The problem of antimicrobial resistance

Antimicrobial resistance (AMR) is one of the world’s most serious public health problems. Many of the microbes (bacteria, viruses, protozoa) that cause infectious disease no longer respond to common antimicrobial drugs (antibacterial drugs including antibiotics, antiviral and antiprotozoal drugs). The problem is so serious that unless concerted action is taken worldwide, we run the risk of returning to the pre-antibiotic era when many more children than now died of infectious diseases and major surgery was impossible due to the risk of infection. The major infectious diseases kill over 11 million people per year. Box 1 shows some AMR prevalence rates, which can vary widely between and within countries, and over time.

Box 1 AMR global prevalence rates

Malaria

• chloroquine resistance in 81/92 countries

Tuberculosis (TB)

• 0-17% primary multi-drug resistance

HIV/AIDS

• 0-25% primary resistance to at least one antiretroviral drug

Gonorrhoea

• 5-98% penicillin resistance in Neisseria gonorrhoeae

Pneumonia and bacterial meningitis

• 0-70% penicillin resistance in Streptococcus pneumoniae

Diarrhoea: shigellosis

• 10-90% ampicillin resistance, 5-95% cotrimoxazole resistance

Hospital infections

• 0-70% resistance of Staphylococcus aureus to all penicillins and cephalosporins

Source: WHO country data, 2000-03

In many countries, antimicrobials are bought directly from drug outlets without a prescription or advice from a trained health professional.

Doctors’ response to AMR has been to switch patients from older antibiotics to newer ones, but new development of these is declining as the pharmaceutical industry has shifted from antibiotics to developing other medicines with potentially larger markets (e.g. for chronic non-infectious illness). Even if new antibiotics are developed, resistance to them would also develop; so prudent use of antibiotics is essential to maintain their effectiveness for future generations.

Serious clinical and financial consequences result from AMR. Morbidity and mortality are increased by delays in administering effective treatment for infections caused by resistant microorganisms. Prolonged illness and hospitalisation are costly and the use of drugs other than first-line drugs may increase costs 100-fold (Fig. 2) making them unaffordable for many governments and patients especially in developing countries.